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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    
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<script>
    // 1. 给一段文章中的全部指定词语进行过滤
       // 比如我要过滤 "SM"
   
   var str = 'asdasdSMasdasdasdSMsdasdasdSMsadasd'
   
   // 需要结果
   // asdasd**asdasdasd**sdasdasd**

   var res = str.replace('SM','**');

   while(res.indexOf('SM') !== -1){
       res = res.replace('SM','**')
   }
   console.log(res);
   
</script>
</html>